Thread-controlling mechanism for sewing-machines.



c. F. GRAY. THREAD CONTROLLING MECHANISM FOR SEWING MACHINES. APPLICATION FILED APBJ, 1911.

1,020,090. I Patented Mar. 12, 1912.

l/V VENTOR ,4 TTOR/VEY COLUMBIA PLANOGRAPH 0.. WASHINGTON- D- c.

UNITED s'rArnsingENT OFFICE.

CHARLES FREDERICK GRAY, F SIERRA MADRE, CALIFORNIA, ASSIGNOR TO THE SINGER MANUFACTURING COMPANY, A CORPORATION OF NEW JERSEY.

THREAD-CONTROLLING MECHANISM FOR SEWING-1VIACHINES.

To all whom it may concern:

Be it known that I, CHARLES F. GRAY, a

. citizen of the United States, residing at Sierra Madre, in the county of Los Angeles and State of California, have invented certain new and useful Improvements in Thread-Controlling Mechanism for Sewing- Machines, of which the following is a speci fioation, reference being had therein to the accompanying drawings.

This invention relates to improvements in needle thread controlling mechanism for sewing machines, and has for its object to provide improved means for controlling, tensioning and strengthening the needle thread as it is fed from the supply to the needle eye.

The successful operation of a high speed sewing machine depends largely upon the degree of utility of the means employed for preparing the needle thread for the stitching operation, and owing to the increased tension required and the liability of the thread, especially if hard twisted, to kink or twist upon itself, causing it to be broken at the point of tension, such preparation of the thread is more dilficult when stitching at high speed (3000 or more stitches per minute) than when operating at a speed of 2000 or less stitches per minute.

In the manufacture of garments it is the common practice when commencing a seam to first form a tack or tie by slightly raising the cloth-presser and manually shifting the fabric under the needle, the same operation being repeated at the completion of the seam. And when the product comprises short seams, high speed has heretofore been of little, if any, advantage as the excessive needle thread tension required makes it difficult to manually shift the fabric without causing the needle to descend on the needleplate, whereas the tension required for the slower speed permits the thread to be drawn through the needle eye without interfering with the stitch-forming movements of the needle. Accordingly, the disadvantages hitherto arising from the excessive needle thread tension necessary in connection with high speed sewing machines have deprived such machines of their full range of application.

Specification of Letters Patent.

Application filed April 7, 1911.

Patented Mar. 12, 1912.

Serial No. 619,463.

the sewing machine and insure that the needle thread will be fed to the action of the stitch-forming mechanism in its normal condition, and to this end there is provided a thread controlling and tensioning device which produces a tension on the needle thread proportionate to the speed at which the thread passes therethrough and acts upon the thread to hold it in straight line position as it leaves said device.

In the accompanying drawings illustrating the invention, in the several figures of which like parts are similarly designated, Figure l is a perspective, infront side elevation, of a sewing machine of ordinary construction equipped with the present invention. Fig. 2 is a detail perspective View of the thread controlling and tensioning device shown in Fig. 1, the tension pins being shown adjusted to receive the needle thread.

As the sewing machine herein represented is of ordinary construction, it has been deemed sufllcient to illustrate only such elements as are essential to an understanding of the invention. I

1 represents the bed-plate of the sewing machine upon which is mounted the bracket arm 2, 3 the band or hand wheel operatively connected with the needle-bar 1 by a suitable main or needle-bar-driving shaft (not shown), 5, 0 and 7 the needle thread check, tension, and take-up, respectively, all of which are of ordinary construction and may be as herein shown or of any other approved form.

8 represents the base-plate of the thread controlling and tensioning device, said base plate being secured by screws, as 9, to the bracket 2, and provided at one edge with a vertically-arranged tension pin plate 10 into which is secured one end of the tension pins 11, 12, 13, 1 .11 and 15, each of which is provided with a hub or enlarged portion, as 1(5.

17 represents a second tension pin plate hinged at one end upon the tension pin 15 and provided with tension pins 18, 19, 20, 21 and 22, each of which is provided with a hub or enlarged portion, as 23, complemental to the enlarged portion 16 of the oppositely secured tension pins.

24 represents a spring catch secured by suitable rivets, as 25, to the base-plate 8, the upper or free end of said catch coacting with the opening or notch 26 formed in the plate 17 to hold the oppositely secured tension pins in alternate relationship, as illustrated in Fig. 1, the hinging of the plate 17 effecting convenient means for passing the thread over and under the respective pins.

It has been found that by passing a thread over and under alternately positioned pins as herein shown a tension on the thread is effected; and it has been demonstrated that the degree of tension exerted on the thread-is proportionate to the speed at" which the thread is withdrawn from between said pins; and that when the thread enters between the pins in a knotted or twisted condition, as shown in Fig. 1, the drag on it is suflicient to cause it to be straightened and delivered to the tension 8 (hereinafter referred to as the second tension) in its normal condition.

In the practical application of the present invention, the second tension device is ad justed to effect a comparatively light tension on the needle thread, to which is added the tension exerted by the device of the invention, the two tension devices normally eX- erting a tension substantially that required for ordinary speed, and the tension necessary to meet the requirements of increased speed is effected by the increased speed at which the thread is withdrawn from be tween the tension pins.

Claims 1. In a thread cont-rolling and tensioning device for sewing machines, the combination of a base-plate mounted on the bracket arm of the sewing machine and provided with a. tension pin plate carrying multiple threadtension pins, a second tension pin plate mounted adjustable with respect to said first mentioned tension pin plate and carrying multiple thread-tension pins, said tension pins coacting to guide the needle thread in a serpentine line as it passes from the receiving to the delivery end of said thread controlling and tensioning device, and a second thread-tension device carried by said bracket arm and located intermediate the point of stitch formation and the delivery end of said thread controlling and tensioning device.

2. In a thread controlling and tensioning device for sewing machines, the combination of a base-plate mounted on the bracket arm of the sewing machine and provided with a tension pin plate carrying multiple threadtension pins, a second tension pin plate mounted adjustable with respect to said first mentioned tension pin plate and carrying multiple thread-tension pins, said tension pins having enlarged portions for directing the needle thread away from the free ends of the pins of the cooperating plate and coacting to guide the needle thread in a serpentine line as it passes from the receiving to the delivery end of said thread controlling and tensioning device, and a second thread-tension device carried by said bracket arm and located intermediate the point of stitch formation and the delivery end of said thread controlling and tensioning device.

3. In a thread controlling and tensioning device for sewing machines, the combination of a base-plate mounted on the bracket arm of the sewing machine and provided with a tension pin plate carrying multiple threadtension pins, a second tension pin plate secured in hinged relationship with respect to said first mentioned tension pin plate and carrying multiple thread-tension pins, said tension pins coacting to guide the needle thread in a serpentine line as it passes from the receiving to the delivery end of said thread controlling and tensioning device, and a second thread-tension device carried by said bracket arm and located intermediate the point of stitch formation and the delivery end of said thread controlling and tensioning device.

4. In a thread controlling and tensioning device for sewing machines, the combination of a base-plate mounted on the bracket arm of the sewing machine and provided with a tension pin plate carrying multiple threadtension pins, a second tension pin plate mounted adjustable with respect to said first mentioned tension pin plate and carrying multiple thread-tension pins, said tension pins coacting to guide the needle thread in a serpentine line as it passes from the receiving to the delivery end of said thread controlling and tensioning device, means for locking said pins in operative relationship, and a second thread-tension device carried by said bracket arm and located intermediate the point of stitch formation and the delivery end of said thread controlling and tensioning device.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

CHARLES FREDERICK GRAY.

Witnesses:

SUSAN H. MEAD, A. S. MEAD.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G. 

